The invention relates to improvements in internally threaded fasteners, and more particularly to improvements in internally threaded fasteners of the type wherein a nut carries a neck at one of its axial ends and the neck is surrounded by a ring-shaped member (hereinafter called washer for short). Fasteners of such character can be utilized, for example, to separably secure the hub of a wheel to an axle of a motor vehicle.
The invention also relates to a novel and improved method of making composite internally threaded fasteners of the above outlined character.
It is already known to provide a nut with an internally threaded main section having a non-circular external outline so that it can be readily engaged and rotated by a wrench or another suitable tool or implement, and to make one axial end portion of the main section of one piece with a neck which is adjacent an external shoulder of the main section and is surrounded by a washer. That end of the neck which is remote from the shoulder is deformed (particularly expanded) so that it prevents unintentional separation of the washer from the nut and it maintains (or can maintain) the washer in close proximity to or in actual contact with the shoulder of the main section. The remote end of the neck can be deformed to overlie the radially innermost portion of that end face of the washer which faces away from the main section and its shoulder.
In accordance with a presently known procedure, a blank is converted into a nut having a main section and a neck by resorting to a press forging or an analogous operation which involves a heating of the blank. The neck is thereupon subjected to a separate cold forming treatment or to a separate turning treatment in order to increase its inner diameter beyond the root diameter of the internal thread of the main section. Thus, the deformation of the neck (in order to couple the washer to the nut) takes place subsequent to the making of an internal thread in the nut.